drm/msm/dp: fix the controller programming sequence

Fix the controller programming sequence to ensure that all
hardware configuration (MSA, transfer unit, timing, etc.) are
done before the timing engine is enabled. This ensures the
controller is in the correct state before video data starts
flowing.

CRs-Fixed: 2250510
Change-Id: Ib77574afe01e5fb88e97bff740de7fba77afa900
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>